As the title states, how often is the standard? I have never used a moisture/oil separator on my Nomad 2 for 2.5 years or a hand pump before that and when I have looked inside the bottle or tube it has looked fine, I have a new YH and just fill my guns or small 90 I live in SE Michigan it’s humid in the summer and cold in the winter and I fill I A/C conditions in the summer. Just curious as a standard.